Ink-removing compound



Patented Sept. 23, WZfi.

stares ORME WELSH, OF GREEN BAY, WISCONSIN.

INK-REMOVING COMPOUND.

No Drawing.

This invention relates to improvements in ink removing compounds.

It is the object of this invention to provide a chemical agent of novel character 6 which can be effectively and economically used to make commercially practicable the removal of ink from printed paper, whereby the paper which is now being Wasted may be reclaimed and used again.

I am aware that there are many formulae heretofore used in the compounding of bleaching or ink removing agents and that such formulae have been employed with varying degrees of success. Some of the compounds heretofore used include certain ingredients of the agent forming the subject matter of the present application, but I am aware of no substance in the prior art whereby the removal of ink from paper may be accomplished as economically and effectively I as by the present formula, due regard being had for the preservation of the fibers of which the paper web is composed.

The preferred composition of this compound for removing ink is as follows:

I Asolution of silicate of soda of about 64 Baum test may, for convenience, be designated as solution A. The sodium silicate solution above indicated is commercially available and is sometimes known as waterglass.

A second solution used in compounding this de-inking agent may be designated solution B. It is composed of 100 pounds of resin to 7 pounds of soda ash NA CO, with water sufiicient to make a thick syrupy mixture. To this mixture approximately 23 times the same volume of water is added to make what is commercially knpwn as, milk of resin. This milk of resin comprises solution B.

Add solution A to solution B in equal parts by volume and dilute as desired to make up the de-inking compound.

While I have indicated that equal parts of solutions A and B should be employed, I have found that other proportions, such as two parts of solution A to three of solution B may be employed to advantage with particular kinds of paper. For papers with high ink content or hard sizing use less water to dilute the compound, or else use a higher proportion of solution'A. Conversely, where the pa 1' has a low ink content or soft size a smal er proportion of solution A may be found practicable.

Application filed November 1, 1924. Serial No. 747,376.

In using my improved de-inking agent I prefer to follow the following process.

I first subject the paper to the action of the compound of solutions A and B. I find that a pound of dry paper will take up about three pounds of solution. The wet solution is then placed in a heater, as usual,-the beater being full of water which further dilutes the solution. In the ordinary beater the paper is agitated or beaten to separate the fibers of which it is composed. The water flows upwardly out of the beater and through a screen. It carries with it a scum including the emulsified ink. The beater above described will be understood to be that which is commonly employed for the treat ment of paper pulp.

The paper, having been re-pulped, is delivered onto the Fourdrin'ier wires of a paper making machine as if it were fresh pulp.

By first treating the waste paper with the solution and subsequently introducing the paper into the beater the solution is enabled to work upon the paper while concentrated, and the effect is as good as if the entire contents of the beater were made up of the deinking compound at the required strength. The smaller quantity which is used preliminary to the introduction of the paper to the beater results in great economy in conducting the de-inking process.

The preliminary treatment of the paper with the de-inking compound may be conducted either in the presence of heat or at. ordinary atmospheric temperatures, and the paper may be agitated during such treatment or ma be allowed to remain at rest. Where agitation and heat, or either of these agencies act upon the paper during the treatment thereof with the de-inking compound, the time required for the de-inking operation will be somewhat decreased. At all events, however, it is not necessary to subject the paper to the action of the de-inking compound for a much longer time than is necessary to insure that the dc-inking compound reaches all parts of the paper.

I am aware that sodium silicate has been very commonly used for removing ink. I am not aware, however, that sodium silicate has been employed with resin size or milk of resin in such proportions as to produce the results contem lated in the present invention. I may a d that I regard the proportions as bem important to secure the est results, alt ough there is a certain Cal amount of variation possible, as above indicated, for the purpose or" removing ink from different kinds of Waste material.

Most compounds heretofore employed for the purpose of de-inkingpaper have not been successful from a practicable commercial standpoint, and one of the reasons to which I attribute this lack of success consists in the fact that the use of such solutions frequently requires breaking down the fibers of the paper. It is my theory of the operation of the compound disclosed herein that the resin size softens up the paper web and permits the fibers thereof to separate readily. The ink is not merely upon the surface of the web but penetrates between the tibe s and into the cellular structure of the fiber. Therefore, if the fibers are not readily separable during the de-inking operation the operation must be conducted to the point where the fibers are actually disintegrated before the ink will be released. It is my belief that milk of resin employed in somewhat the proportions indicated herein has the efi'ect upon the paper of causing its fibers to separate, thereby affording ready access to all parts of the fiber by the sodium silicate. It is well known that the efiect of sodium silicate upon ink consists in the saponification or emulsification of the ink whereby the ink is floated to the surface to be removed in the form of scum as aforesaid. Obviously, anything which assists sodium silicate in reaching the ink will greatly expedite the de-inking process and will also render the product more desirable by preserving the original fibers against mutilation and maceration.

I claim:

1. The process of removing ink from paper which includes the treatment of the paper with a saponifying agent in the presence of a resinous compound.

2. The process of de-inking paper which consists in treating the paper with a comparatively concentrated solution of sodium siliate and milk of resin and subsequently subjecting the paper to agitation in the presence of a quantity of water, whereby such solution is greatly diluted.

3. The process of removing ink from paper which consists in treating the paper with a comparatively concentrated solution of sodium silicate. mixed with a comparatively weaker solution including rosin, and a small quantity of soda ash.

t. A compound of the character described, comprising approximately equal parts of first and second solutions, said first solution comprising sodium silicate of approximately 65 Baum test, and said second solution comprising 100 pounds of rosin and 7 pounds of soda ash mixed in such proportions with water as to form a thick syrupy mixture and subsequently diluted with amiroximately 223 parts of water.

Cl ME IVELSH. 

